Supporters of Maricopa County Sheriff Joe Arpaio hold a rally at a park in Fountain Hills, Arizona Saturday. Arpaio, who styles himself as "America's toughest sheriff," is known for controversial sweeps cracking down on illegal immigrants in the Mexico border state.

To some, Maricopa County Sheriff Joe Arpaio is the worst law enforcement has to offer, a cop run amok. Others say he's a scapegoat, unfairly vilified for upholding the law.

“All he does is enforce the law that's already on the books,” says Walt Lyons, one of dozens of mostly retirees who attended a Saturday rally and chanted “go Joe, go Joe,” to show they stand behind their sheriff.

As many as 200 people, some holding signs touting the longtime lawman, took part in the event northeast of Phoenix in Fountain Hills, where Mr. Arpaio lives and enjoys strong support even as he faces a federal investigation involving accusations of racial profiling during immigration sweeps. Arpaio maintains he's done nothing wrong and is merely doing the job the federal government neglects.

The rally came just three days after the Supreme Court took up Arizona's tough immigration law known as Senate Bill 1070. Although it wasn't the first law passed to encourage the departure of illegal immigrants from the state, the far-reaching 2010 measure decisively split Arizonans into warring political factions. On one hand, Arpaio, a staunch advocate of SB 1070, gets high praise from his neighbors and on the other, the state senator who conceived the immigration law gets ousted from office.

A federal judge in July 2010 prevented the most controversial provisions from taking effect, including one that requires police to check the immigration status of those suspected of being in the country illegally. The United States Supreme Court is expected to issue its ruling in June.

But the illegal immigration debate is much more complicated than people just taking sides on SB 1070, Mr. Merrill says.

State polls consistently show that 60 percent or more of Arizonans generally favor the law and want toughened border security. But according to a statewide poll released April 26, three quarters of registered voters support the federal Dream Act that would allow children of illegal immigrants who graduate from college or serve in the military to obtain legal status. The proposed legislation has languished in Congress for years.

Merrill, who directed the latest poll, says the Dream Act drew favorable reaction not just from Democrats and Latinos, but also from independent and Republican voters. The results show that seven out of 10 non-Hispanics support it.

“People make a distinction,” he says. “Illegal immigration is a complex set of issues.”

The climate changed when Ms. Napolitano went to Washington and Jan Brewer, the former state secretary, inherited the post. Until she signed SB 1070 into law in April 2010, political observers gave Ms. Brewer, a Republican, little chance of winning a full term in office.

“A lot of people got comfortable,” knowing that the buck always stopped with the Democratic governor, recalls Randy Parraz, a key player in the recall election that made bedfellows of Republicans who disliked Pearce's politics and those pushing for immigration reform.

Mr. Parraz, an Arpaio critic, notes that Pearce was defeated by a fellow Republican who opposes the state's crackdown on illegal immigration and gifts from special interest groups. (Pearce was involved in a scandal involving political contributions and the Fiesta Bowl college football tournament).

Parraz and his allies repeatedly have called for the resignation of Arpaio, who says he won't step down. His decision to run for a sixth term in the state's most populous county in November has made him the next target for his foes. A “massive effort” to persuade Maricopa residents to vote for an Arpaio opponent will kick off in the summer, Parraz notes.